From d4bc5f7f1098c40c0e88b8e2b07bd335dc0fa137 Mon Sep 17 00:00:00 2001
From: Rokas Puzonas <rokas.puz@gmail.com>
Date: Sun, 21 Jan 2024 11:48:15 +0200
Subject: [PATCH] center chip8 screen in the middle

---
 src/main-scene.zig  | 19 ++++++++++++++++++-
 src/raylib-chip.zig | 23 +++++++++++++++++------
 2 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/src/main-scene.zig b/src/main-scene.zig
index 6c72bcd..aa6c459 100644
--- a/src/main-scene.zig
+++ b/src/main-scene.zig
@@ -84,5 +84,22 @@ pub fn update(self: *Self, dt: f32) void {
 pub fn draw(self: *Self) void {
     rl.ClearBackground(rl.Color{ .r = 33, .g = 33, .b = 33 });
 
-    self.raylib_chip.render();
+    const display_width = self.chip.display_width;
+    const display_height = self.chip.display_height;
+    const screen_width = rl.GetScreenWidth();
+    const screen_height = rl.GetScreenHeight();
+
+    const x_scale = @as(f32, @floatFromInt(screen_width)) / @as(f32, @floatFromInt(display_width));
+    const y_scale = @as(f32, @floatFromInt(screen_height)) / @as(f32, @floatFromInt(display_height));
+    const max_scale = @min(x_scale, y_scale);
+
+    const render_width: i32 = @intFromFloat(@as(f32, @floatFromInt(display_width)) * max_scale);
+    const render_height: i32 = @intFromFloat(@as(f32, @floatFromInt(display_height)) * max_scale);
+
+    self.raylib_chip.render(
+        @divTrunc(screen_width - render_width, 2),
+        @divTrunc(screen_height - render_height, 2),
+        render_width,
+        render_height
+    );
 }
diff --git a/src/raylib-chip.zig b/src/raylib-chip.zig
index ae763c3..c710b74 100644
--- a/src/raylib-chip.zig
+++ b/src/raylib-chip.zig
@@ -83,14 +83,25 @@ pub fn update(self: *Self, dt: f32) void {
     }
 }
 
-pub fn render(self: *const Self) void {
-    rl.DrawRectangle(0, 0, self.chip.display_width, self.chip.display_height, self.off_color);
+pub fn render(self: *const Self, x: i32, y: i32, width: i32, height: i32) void {
+    const display_width = self.chip.display_width;
+    const display_height = self.chip.display_height;
+    const x_scale = @as(f32,@floatFromInt(width)) / @as(f32, @floatFromInt(display_width));
+    const y_scale = @as(f32,@floatFromInt(height)) / @as(f32, @floatFromInt(display_height));
 
-    for (0..self.chip.display_height) |y| {
-        for (0..self.chip.display_width) |x| {
-            if (self.chip.display_get(@intCast(x), @intCast(y))) {
-                rl.DrawRectangle(@intCast(x), @intCast(y), 1, 1, self.on_color);
+    rl.rlPushMatrix();
+    rl.rlTranslatef(@floatFromInt(x), @floatFromInt(y), 0);
+    rl.rlScalef(x_scale, y_scale, 1);
+
+    rl.DrawRectangle(0, 0, display_width, display_height, self.off_color);
+
+    for (0..display_height) |iy| {
+        for (0..display_width) |ix| {
+            if (self.chip.display_get(@intCast(ix), @intCast(iy))) {
+                rl.DrawRectangle(@intCast(ix), @intCast(iy), 1, 1, self.on_color);
             }
         }
     }
+
+    rl.rlPopMatrix();
 }